Ender's older brother, known for his intelligence and manipulative nature, who is initially rejected by the I.F. for being too aggressive, yet harbors ambitions of political power.

Ender's loving older sister, who protects him from Peter and becomes a successful political writer under an assumed identity while maintaining a complex relationship with her siblings.

An officer in the International Fleet tasked with overseeing and shaping Ender's training at Battle School, known for his tough and often isolating tactics justified by the perceived stakes of their mission.

A bully in Ender's launch group at Battle School, whose initial confrontation with Ender sets the stage for early school dynamics.

A fellow Battle School student who befriends Ender and assists him in integrating within their group, later becoming an excellent squadron leader.

One of the few female students in Battle School, who initially helps train Ender in military tactics and later becomes a trusted ally.

Ender's Salamander Army commander at Battle School, who resents Ender's presence and becomes one of his main adversaries.

A toon leader in Rat Army who recognizes Ender's potential and provides critical support and perspective on the realities of Battle School.

A small but exceptionally intelligent Battle School student in Ender's command, who parallels Ender in many ways and becomes a key member of Dragon Army.

The legendary victor of the Second Invasion against the buggers, who returns to mentor Ender with unique insights and rigorous training.